The present invention relates generally to heat exchangers and, more particularly, to systems for cooling and conditioning air such as in textile mills and similar environments as described in U.S. Pat. No. 4,857,090.
U.S. Pat. No. 4,857,090 sets forth a system that is capable of cooling and conditioning air which has significantly elevated humidity and/or air temperature. This type of system is particularly advantageous for application in textile spinning operations, which frequently employ open-end spinning machines that include rotors which pull in a significant quantity of room air as part of the spinning process, and then exhaust this air back into the room at markedly elevated temperatures. In some typical open-end spinning machines, each rotor pulls in approximately 12 CFM to 13 CFM of air and heats this air approximately 48.degree. F. An open-end spinning machine of this type having 216 rotors will thus exhaust approximately 2700 CFM of air heated to a temperature of approximately 124.degree. F. back into the room where the spinning machines are located.
This heated air generated by open-end spinning rotors can create significant problems in a spinning mill because precise temperature and humidity conditions are required in order to maintain the quality of the yarn formed by the open-end spinning process within acceptable limits. Room temperature is usually maintained within the range of 74.degree. F. to 80.degree. F. and relative humidity within the range of 58% to 62%. While cooling and conditioning systems of the type in U.S. Pat. No. 4,857,090 have proven to efficiently operate under demands such as those found in modern open-end spinning mill applications, the power consumption of these systems may be substantial.
Furthermore, heat exchangers that are employed to cool the water used in the air washers of systems of this type must periodically be cleaned, because foreign matter tends to collect and adhere on the interior surfaces of the heat exchangers, thereby substantially reducing the efficiency of heat transfer between the heat exchanger and the water being cooled. Difficult and time consuming mechanical cleaning is often necessary in order to restore the heat exchanger to its original operating efficiency, and therefore the operating cost of the system may be significantly increased by the expense associated with such cleaning. For systems with closed vessel heat exchangers, the cooling and conditioning system must usually be shut down in order to accomplish cleaning of the heat exchanger, potentially resulting in reduced operating time for the spinning mill itself. Automatic cleaning systems for closed vessel heat exchangers have not proven to be capable of adequately operating in textile mill applications because of the unique nature of textile fibers, which collect in the reservoir of the air washer and then flow into the heat exchanger, where they foul the brushes used in automatic cleaning systems. Cooling systems employing open vessel heat exchangers, which may be more easily cleaned, have not previously been capable of attaining the cooling capacity necessary in modern industrial applications.
In typical installations, the heat exchanger is located centrally and serves a plurality of air washers located at some distance from the heat exchanger. This arrangement requires a significant amount of piping to transport water between the heat exchanger and air washers and creates inefficiencies which reduce the system's cooling capacity. Additionally, the use of a central heat exchanger results in all of such air washers receiving water chilled to substantially the same temperature, although it may be advantageous to provide water at different temperatures to different air washers.
In accordance with the present invention, a heat transfer device, such as may be used in a heat exchanger for cooling water, is provided in which heat transfer efficiency is improved and cleaning requirements are significantly reduced, thereby reducing energy consumption, operating costs, and potential down-time.